Cross-domain interactions induce community stability to benthic biofilms in proglacial streams

Abstract

Cross-domain interactions are an integral part of the success of complex biofilms in natural environments. Here, we report on cross-domain interactions in biofilms of streams draining proglacial floodplains in the Swiss Alps. These streams, as a consequence of the retreat of glaciers, are characterized by multiple environmental gradients and stability that depend on the time since deglaciation. We estimate co-occurrence of prokaryotic and eukaryotic communities along this gradient and show that key community members have disproportionate effects on the stability of co-occurrence networks. The topology of the networks was similar independent of environmental gradients and stability. However, network stability was higher in the streams draining proglacial terrain that was more recently deglaciated. We find that both pro- and eukaryotes are central to the stability of these networks, which fragment upon the removal of both pro- and eukaryotic taxa. These 'keyplayers' are not always abundant, suggesting an underlying functional component to their contributions. Thus, we show that there is a key role played by individual taxa in determining microbial community stability of glacier-fed streams.

The role of phages for microdiverse bacterial communities in proglacial stream biofilms

“…Generally, little is known about viral biodiversity in extreme environments, particularly however in streams and rivers draining mountain regions (Payne et al, 2020;Bekliz et al, 2022;Busi et al, 2022). Here, we expand the current knowledge of phage diversity and its role in shaping microbial communities in streams and rivers.…”

“…Other common AMGs were queE, queD, queE, and folE genes (137 AMG), involved in the synthesis of the deazapurine nucleoside preQ O , which also has been shown to protect viruses from restriction enzymes (Hutinet et al, 2019;Kieft et al, 2020). In contrast to pelagic systems (Kieft et al, 2021b;Heyerhoff et al, 2022) and despite the importance of cross-domain interactions in proglacial stream biofilms (Busi et al, 2022), however, AMGs encoding the core photosystem II proteins psbA and psbD were rare, with only 3 AMGs present across our entire dataset. The majority (34.4%) of AMGs encoded KOs involved in the metabolism of cofactors and vitamins including AMGs involved in folate biosynthesis, the metabolisms of nicotinate/nicotinamide, and porphyrine/chlorophyll.…”

“…Generally, little is known about viral biodiversity in extreme environments, particularly in mountain streams and rivers (Payne et al, 2020;Bekliz et al, 2022;Busi et al, 2022). Here, we identified 1452 high-quality (n=870) or complete (n=582) vMAGs.…”

“…Here, we present insights into the interactions between bacterial biofilm communities and their phages in high-altitude stream ecosystems. Alpine streams are extreme environments, characterized by ultra-oligotrophy, low water temperature, exposure to ultraviolet (UV) radiation, and short ice-free seasons, yet represent hotspots of microbial biodiversity (Freimann et al, 2013;reviewed by: Hotaling et al, 2017;Brandani et al, 2022;Busi et al, 2022;Fodelianakis et al, 2022). Glacier influence adds additional constraints for life in alpine streams.…”